Carburetor



Nov. 7, 1933,

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CARBURETOR Filed Aug. 6. 1928 4 Sheets-Sheet 2 4 Sheets-Sheet 3 C. H. KlRBY CARBURETOR Filed Aug. 6. 1928 Nov. 7, 1933.

Nov. 7, 1933. c. H. KIRBY 1,934,130

CARBURETOR Filed Aug. 6. 1928 4 Sheets-Sheet 4 N N @i ya Fmg .23a a la Jj@ X j@ i l 15a; Jfi 3 i JJ@- mi i:

ai g/*W/-HM/ 4Z 4Q J Il@ IIA 3 l Patented Nov. 7, 1933 UNITED STA CARBUBETOR Charles Il.' Kirby, Flint, Mich., assigner to Marvel Carburetor Company, Flint, Mich., a

corporation of Illinois Application August 6, 1928. Serial No. 297,695

2 Claims.

'I'his invention relates to improvements in carburetors of the character used for furnishing explosive mixtures to internal combustion engines.

The primary object of the invention is to furnish a carburetor with means for constantly supplying fuel from the supply to the outlet passageway at a point posterior to the throttle Valve.

A further object is to provide a carburetor with means for constantly feeding varying amounts of fuel to the outlet passageway above the throttle, in which the variation in feed is controlled by movement of the throttle, the amount fed being gradually diminished to a as the throttle moves from closed to fully open position.

A further object is to furnish means for constantly feeding fuel from the carburetor float chamber to the explosive mixture outlet at a point posterior to the throttle, such means being regulated by conditions in a communicating passageway, which is ported into the entering lip of a Venturi sleeve surrounding the outlet of the main fuel nozzle.

Another object is to provide, in combination with structures of the types mentioned above, means for feeding an auxiliary supply of fuel rapidly to the main nozzle on acceleration; this accelerating supply being added to when necessary by fuel from a well forming part of the carburetor.

In the present invention, a relatively small stream of fuel is discharged into the mixture passageway, above the throttle, which discharge is variable with relation to the position of the throttle, but does not cease all together in any position of the throttle. This stream is mingled with that of the main nozzle, when the throttle is opened to any extent, and it diminishes as the discharge of the main nozzle increases; being modified in its extent by a slightly sub-atmospheric pressure in a chamber communicating with the stream passageway; this sub-atmospheric pressure being due to the position of a port in the entering lip of the Venturi sleeve, and its influence being greater as the velocity of the air entering the Venturi sleeve is increased.

With the foregoing objects outlined and with other objects in view which will appear as the description proceeds, my invention consists in the novel features hereinafter described in detail, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims.

Referring to the drawings,

Fig. 1 is a vertical sectional view of an embodiment of the invention devised especially to facilitate the disclosure of the invention, and showing the relative fuel levels in the various nozzles when the throttle is in fully closed position.

Figs. 2, 3 and 4 are similar views of the same structure, but showing the relative positions of the fuel levels when the throttley is in various positions of opening.

Fig. 5 is a vertical sectional view of an embodiment or of the mechanical expression this invention is to take, certain parts being in elevation, and the section being taken along line 5-5 of Fig. 6.

Fig. 6 is a bottom plan view.

Fig. 7 is a vertical sectional view, taken on line 7--7 in Fig. 6.

Fig. 8 is a similar sectional view, taken on 75 line 8-8 of Fig. 6.

Figs. 9 and ll0 are vertical sectional views of fragments of modifications, showing different arrangements of the main needle valve.

In explaining the invention in connection with Figs. 1 to 4 inclusive, it will be noted that the fuel is fed from any suitable form of oat tank 1, directly to a tube 2, having a nozzle 3, through which a fine stream is fed into an annular chamber 4, the outlet 5 of which is controlled 85 by a needle valve 6. This fuel constantly flows through a duct 7, under suction innuence exerted in the carburetor outlet or main mixture passageway. It will be noted that the duct 7 opens into this passageway posterior to the throttle valve 9, and consequently, fuel will be continuously fed through 2 and 7, due to suction from the engine.

The fuel from the float tank, also passes through an orifice member 10, and in this way, in regulated quantity, enters a passageway 11, from which it flows through another orifice member 12, into a U-shaped conduit 13. A needle valve or the like 14, controls the flow to the U-shaped conduit, and the arms of this conduit communicate with the main nozzle 15, and a auxiliary nozzle 16, the latter being located within a chamber 17.

The outlet of the main nozzle terminates in the flaring outlet of a Venturi sleeve 18, located in the mixture passageway, as is usual in carburetors. A port 19 is located in the entrance lip of the Venturi sleeve, and it communicates. by a passageway 20, with the chamber 17, as well as with a chamber 21, in which the tube 110 tion influence exerted through 19, will normally retard the flow of fuel from the nozzle 16, and will also have a modifying tendency on the fuel passing through duct 7, tending to diminish the flow through 7, when the flow through the main nozzle is increased.

The carburetor is also equipped with an auxiliary well 22, containing a tube 23, into which the' fuel may rise from conduit 1l, by way of passageway 24. The top of the tube 23 is capped and provided with an orifice member 25, the hole in which is of less diameter than the tube 16, whereby under acceleration, when the main fuel nozzle begins to draw on the auxiliary supply, it will first empty the nozzle 16, and afterwards, the well 23, as shown in Figs. 2, 3 and 4, such emptying being brought about during the movement of the throttle from closed to fully open position.

From the foregoing, it may be seen that the discharge through '7 will vary as the throttle 9 moves, but will not cease altogether in any position of the throttle. When the throttle is fully closed, the supply through 7, will be at a maximum, but as the throttle opens, this supply Will be diminished. As before stated, it diminishes as the discharge from the main nozzle 15 increases, and it is modified in its extent by a slightly sub-atmospheric pressure in the chamber 21, due to the position of the port 19 in the entering lip of the Venturi sleeve. This sub-atmospheric influence is greater as the velocity of the air entering the venturi is increased.

Instant acceleration is obtained by the U-tube, made up of the nozzles 15 and 16, and the passageway 13, the discharge rate being modified by the depression or sub-atmospheric pressure in the passageway 20, so that the higher the speed, of the motor, the less the additional discharge for acceleration purposes.

The Well 23 is for the double purpose of prolonging the accelerating charge, and of thinning out the mixture at high speeds by placing subatmospheric pressure on the fuel therein.

A commercial embodiment of the invention is shown in Figs. 5 to 8' inclusive, and to avoid repetition, the parts in these figures have been 1,984,180 2 is located. Due to this arrangement, sucmarked with the same reference characters as are employed in Figs. 1 to 4 inclusive, but in each instance, the letter a is added to the figure.

A choke valve 26 is shown in the commercial embodiment, and its equivalent is not illustrated in Figs. 1 to 4 inclusive.

In the commercial embodiment, it will be noted that the needle valve 14a directly coacts with the passageway 11a, but if desired, the needle valve might be used with the orifice member 10b, as shown in Fig. 9, or could be used with the orifice member 12b, as in Fig. 1.

From the foregoing, it is believed that the construction, operation and advantages of the invention may be readily understood, and it is apparent that various changes may be made in the details disclosed without departing from the spirit of the invention, as expressed in the claims.

What is claimed and desired to be secured by Letters Patent is:

1. In a carburetor, a mixture passageway, a throttle valve in the passageway, a U-shaped conduit, one arm of said conduit forming a fuel nozzle discharging into the mixture passageway a supply chamber, means for leading fuel from the supply chamber to the U-shapecl conduit, a second conduit for leading fuel from the supply chamber to the mixture passageway at a point posterior to the throttle valve, and passage means placing the other arm of the U-shaped conduit and said second conduit in communication with the mixture passageway.

2. In a carburetor, a mixture passageway, a throttle valve arranged in the passageway, a U- shaped conduit, one arm of which forms a fuel nozzle discharging into the passageway, a supply chamber, a well, a passageway placing the supply chamber and well in communication with the U-shaped conduit, another passageway for leading fuel from the supply chamber to the mixture passageway, posterior to the throttle valve, and means placing the last mentioned passageway, the well and the other arm of the U-shaped conduit, in communication with the mixture passageway, anterior to the valve.

CHARLES H. KIRBY. 

